The objective of this study is to re-evaluate the relation of diabetes and atherosclerosis in the rabbit and to develop a model of these diseases in a small laboratory animal. Diabetic (alloxan), subdiabetic and control animals will be fed either a very low cholesterol semisynthetic atherogenic diet or one containing no cholesterol at all. Serum lipids will be quantitated and characterized using salicic acid chromatography, paper electrophoresis and ultracentrifugation methods. Arterial lesions will be quantitated and evaluated in-the-gross and by light and electron microscopic methods. In previous studies of the relation of diabetes and atherosclerosis in rabbits, animals were fed very large amounts of cholesterol (0.5-3.0%). Such feeding results in a number of alterations in lipid metabolism and transport not found in human atherosclerotics. Moreover, the arterial lesions so produced are dissimilar to human atherosclerosis in many respects. Considerable experience in our laboratory has shown that nondiabetic rabbits fed either of the proposed atherogenic diets develop arterial lesions that are similar to fatty-fibrous atherosclerotic plaques in man in the absence of the extreme lipid storage disease seen when excess dietary cholesterol is fed. The feeding time (9 mos.) has been selected so that it will be possible to recognize and quantitate either enhancement or retardation of atherogenesis in the diabetic and subdiabetic state. This will be the first study of the relation of diabetes and atherosclerosis using newer and improved feeding techniques to induce arterial lesions in rabbits. If successful, the study will provide a most important model in which a number of dietary and hormonal factors could be evaluated in future studies.